Police arrested about 75 Buddhist monks, rabbis, priests and other clerics here Friday, and about a dozen other protesters linked with plastic piping were arrested in Washington near the White House.
The arrests were the latest of several thousand detentions nationwide since the United States went to war against Iraq.
In San Francisco, home to perhaps the most active U.S. antiwar movement, the protesters gathered at the city's federal building.
"We are here as Jews, Christians, Muslims and Buddhists to proclaim that the world can be healed," Rabbi Michael Lerner said at an interfaith service.
In Washington, antiwar protesters blocked traffic on 14th Street and Pennsylvania Avenue, two blocks from the White House, by linking themselves with plastic piping.
Police took away the 13 protesters during the morning rush hour. Police Chief Charles Ramsey said officers had to cut off the pipes before the protesters could be taken away.
Another group of antiwar demonstrators dressed in colorful circus attire protested on the sidewalk nearby, carrying placards bearing slogans such as "Greed" and "Justice."